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Title (Primary) Spatial and temporal variability in concentration-discharge relationships at the event scale
Author Musolff, A.; Zhan, Q.; Dupas, R.; Minaudo, C.; Fleckenstein, J.H.; Rode, M.; Dehaspe, J.; Rinke, K.
Journal Water Resources Research
Year 2021
Department ASAM; SEEFO; HDG
Volume 57
Issue 10
Page From e2020WR029442
Language englisch
Topic T5 Future Landscapes
Supplements https://agupubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1029%2F2020WR029442&file=2020WR029442-sup-0001-Supporting+Information+SI-S01.docx
Keywords water quality; nutrients and nutrient cycling; catchment; time series analysis
Abstract The analysis of concentration-discharge (C-Q) relationships from low-frequency observations is commonly used to assess solute sources, mobilization, and reactive transport processes at the catchment scale. High-frequency concentration measurements are increasingly available and offer additional insights into event-scale export dynamics. However, only few studies have integrated inter-annual and event-scale C-Q relationships. Here, we analyze high-frequency measurements of specific conductance (EC), nitrate (NO3-N) concentrations and spectral absorbance at 254 nm (SAC254, as a proxy for dissolved organic carbon) over a two year period for four neighboring catchments in Germany ranging from more pristine forested to agriculturally managed settings. We apply an integrated method that adds a hysteresis term to the established power law C-Q model so that concentration intercept, C-Q slope and hysteresis can be characterized simultaneously. We found that inter-event variability in C-Q hysteresis and slope were most pronounced for SAC254 in all catchments and for NO3-N in forested catchments. SAC254 and NO3-N event responses in the smallest forested catchment were closely coupled and explainable by antecedent conditions that hint to a common near-stream source. In contrast, the event-scale C-Q patterns of EC in all catchments and of NO3-N in the agricultural catchment without buffer zones around streams were less variable and similar to the inter-annual C-Q relationship indicating a homogeneity of mobilization processes over time. Event-scale C-Q analysis thus added key insights into catchment functioning whenever the inter-annual C-Q relationship contrasted with event-scale responses. Analyzing long-term and event-scale behavior in one coherent framework helps to disentangle these scattered C-Q patterns.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=25166
Musolff, A., Zhan, Q., Dupas, R., Minaudo, C., Fleckenstein, J.H., Rode, M., Dehaspe, J., Rinke, K. (2021):
Spatial and temporal variability in concentration-discharge relationships at the event scale
Water Resour. Res. 57 (10), e2020WR029442